Hi Mr.AdsGig
Edit the file oc-includes/osclass/controller/item.php
Go to case 'item_add_post': at the bottom of this case statement .you'll find the following code
$category = Category::newInstance()->findByPrimaryKey(Params::getParam('catId'));
View::newInstance()->_exportVariableToView('category', $category);
$this->redirectTo(osc_search_category_url());
Comment the above code and add the following code
$item = osc_apply_filter('pre_show_item', Item::newInstance()->findByPrimaryKey( $itemId ));
View::newInstance()->_exportVariableToView('item', $item);
$this->redirectTo(osc_item_url());
Then it'll redirect to the latest posted ad by user after publishing.